Living body communication in which communication data are transmitted and received through living bodies such as human bodies has been drawing attention. The living body communication is expected an application for medical and health care services, short-range wireless communication practices, in-vehicle wireless communication operations, amusement activities, and the like. The living body communication can significantly reduce power consumption as compared to some conventional wireless communication techniques.
In the living body communication, each communication apparatus configured to use a living body as part of a transmission path is provided with two electrodes. One is a signal electrode connected to a signal line, and the other is a reference potential electrode connected to ground potential of the communication apparatus having reference potential. The signal electrodes of the respective communication apparatuses are electrically connected together mainly through the living body, while the reference potential electrodes of the respective communication apparatuses are electrically connected together mainly through the space or the earth. Thereby, each communication apparatus transmits the potential difference between the signal electrode and the reference potential electrode to the counterpart communication apparatus.
In the case where a living body communication apparatus that uses electric fields on surfaces of living bodies is applied to a system to perform ID authentication of individuals, living bodies cause capacitance coupling when the living bodies come close to each other. Accordingly, there is a problem of difficulty in associating an ID of each individual with the living body communication apparatus due to an increase in crosstalk, which is inherent in the living body communication that uses the living body as a transmission path.